The present invention relates to back lighted display signs, and more particularly to such signs which are formed by modules that can be combined side-by-side to form a wide variety of different sized and shaped sign assemblies.
Above a counter in fast food restaurants, there is often a large sign presenting the menu and prices of food items offered for sale. Typically, these signs consist of a number of panels with each panel displaying a different category of items. For example, one panel may list hot sandwiches, with another panel for cold sandwiches, and yet another panel listing beverages and desserts. A panel may also display a photographic reproduction of a food item being offered for sale as a way in which to create customer interest. Quite often these signs are back lit with the lettering and photographic image being translucent to emit light.
Because the display area varies from restaurant to restaurant, and because of a need to create a distinctive appearing sign for various restaurants, modular sign systems have been devised. Previously, such signs were created by side-by-side combinations of a number of square modules having a frame which contain light bulbs over which a translucent message panel was mounted. Such square units could be combined in horizontal and vertical lines, or in a two-dimensional array to form different sized and shaped sign assemblies.
Often, the individual modules of the sign assembly had to be attached together so that the entire display could be suspended from a ceiling or mounted in some other fashion as a single unit. It is therefore desirable to provide a mechanism by which the different modules can be attached to one another without visible fastening mechanisms or the need for special tools. Furthermore, since each module contains its own lamp assembly, a mechanism for supplying electrical current to each module has to be provided. It is undesirable to have a separate external cord for each module as the number of such cords because of the numerous cords that would extend from a large sign assembly. It is also desirable to provide a mechanism by which a trim frame can be attached around the perimeter of the assembled sign in order to create a decorative appearance to the overall sign and set it apart from its surroundings.